<?php
// +----------------------------------------------------------------------
// | TOPThink [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2010 http://topthink.com All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

defined('THINK_PATH') or exit();
/**
 * 系统行为扩展：表单令牌生成
 * @category   Think
 * @package  Think
 * @subpackage  Behavior
 * @author   liu21st <liu21st@gmail.com>
 */
class TokenBuildBehavior extends Behavior {
	// 行为参数定义
	protected $options   =  array(
        'TOKEN_ON'       => false,     // 开启令牌验证
        'TOKEN_NAME'     => '__hash__',    // 令牌验证的表单隐藏字段名称
        'TOKEN_TYPE'     => 'md5',   // 令牌验证哈希规则
        'TOKEN_RESET'    => true, // 令牌错误后是否重置
	);

	public function run(&$content){
		if(C('TOKEN_ON')) {
			if(strpos($content,'{__TOKEN__}')) {
				// 指定表单令牌隐藏域位置
				$content = str_replace('{__TOKEN__}',$this->buildToken(),$content);
			}elseif(preg_match('/<\/form(\s*)>/is',$content,$match)) {
				// 智能生成表单令牌隐藏域
				$content = str_replace($match[0],$this->buildToken().$match[0],$content);
			}
		}else{
			$content = str_replace('{__TOKEN__}','',$content);
		}
	}

	// 创建表单令牌
	private function buildToken() {
		$tokenName  = C('TOKEN_NAME');
		$tokenType  = C('TOKEN_TYPE');
		if(!isset($_SESSION[$tokenName])) {
			$_SESSION[$tokenName]  = array();
		}
		// 标识当前页面唯一性
		$tokenKey   =  md5($_SERVER['REQUEST_URI']);
		if(isset($_SESSION[$tokenName][$tokenKey])) {// 相同页面不重复生成session
			$tokenValue = $_SESSION[$tokenName][$tokenKey];
		}else{
			$tokenValue = $tokenType(microtime(TRUE));
			$_SESSION[$tokenName][$tokenKey]   =  $tokenValue;
		}
		$token      =  '<input type="hidden" name="'.$tokenName.'" value="'.$tokenKey.'_'.$tokenValue.'" />';
		return $token;
	}
}